1. Field of the Invention
The present invention relates to a battery pack apparatus, and more particularly to an external battery pack apparatus additionally mounted to a portable appliance having an internal battery.
2. Description of the Related Art
Typically, an external dummy pack manufactured by Electro Fuel Company has been widely used to increase a usable time of a portable appliance while a user carries the portable appliance. Such an external dummy pack adopts one of various kinds of adapters on the basis of a connector type of a portable appliance, so that an appropriate adapter based on a connector form of the portable appliance is selectively mounted to the external battery back. A power-supply voltage is applied to the portable appliance via the adapter.
However, a voltage or a current to be applied to the portable appliance may be different among respective portable appliances, but the above conventional external dummy pack has no solution for this problem.
A representative example for varying such a voltage and current is described in U.S. Pat. No. 6,091,611. The technique shown in this patent connects resistant elements between two cable conductors inside of a connector of a cable terminal, and a power-supply unit varies an output voltage and an output current by detecting resistance values of the resistant elements at its own output terminal.
However, such a technique has a disadvantage in that a size of the connector becomes greater because resistant elements should be contained in the connector. Also, since a PWM (Pulse Width Modulation) IC is directly or indirectly controlled according to a resistance value of a connector, electrical signal attenuation is generated by a length of a cable, resulting in deterioration of system reliability.
In the meantime, such an external battery pack apparatus has a disadvantage in that it cannot effectively use a smart communication function supported by a conventional internal battery pack apparatus. This smart communication function means a specific function for providing a portable appliance of which a battery serves as a host with either a variety of information, i.e., an effective lifetime of a battery, the number of charging/discharging operations of the battery, and a current charged state or a usable time of the battery, or basic information for computing the information.
Therefore, the present invention has been made in view of the above problems, and provides an external battery pack apparatus having simplified connector and cable to supply an output power to a portable appliance.
The present invention provides an external battery pack apparatus for reliably programming an output power.
Further, the present invention provides an external battery pack apparatus having a smart communication function for a portable appliance to recognize status information of a battery.
In accordance with the present invention, an external battery pack apparatus for providing a portable appliance with a power-supply voltage, comprises: an adapter for comprising a power-supply terminal and output voltage setting terminals, and programming an output voltage by short-circuiting or open-circuiting at least one among the terminals; a cable connected to the adapter; and a main body comprising a battery, a charging controller for charging the battery, and an output controller for performing a DC-to-DC conversion on a voltage charged in the battery and outputting the DC-to-DC converted voltage to the adapter via the cable, detecting a programming status of the adapter, and varying an output voltage in response to the detected programming status.
Preferably, the output controller may include an adapter detector for generating different resistance values in response to a programming status of terminals of the adapter, and a DC/DC converter for converting an output DC voltage according to a signal value of an output signal of the adapter detector.
Preferably, the external battery pack apparatus further includes a central controller for checking a charging/discharging state of the battery by controlling the charging controller, and a communication port connected to the central controller, for transmitting the charging/discharging state information of the battery to a portable appliance.